COMBINATION OIL RING

摘要

A combination oil ring includes a pair of upper and lower side rails and a spacer expander arranged there between, the spacer expander including a plurality of upper pieces and lower pieces alternately arranged in a circumferential direction with the pieces axially and circumferentially apart from each other, a coupling piece coupling pieces adjacent to each other, and flange portions formed standing at inner circumferential-side end portions of the upper pieces and the lower pieces so as to press the side rails, and a through hole being formed in the flange portions, wherein side rail support portions that project axially are formed at portions in the circumferential direction of outer circumferential-side end portions of the upper pieces and the lower pieces.

主权项

1. A combination oil ring comprising a pair of upper and lower side rails and a spacer expander arranged there between, the spacer expander including a plurality of upper pieces and lower pieces alternately arranged in a circumferential direction with the pieces axially and circumferentially apart from each other, a coupling piece coupling an upper piece and a lower piece adjacent to each other, and a flange portion formed standing at an inner circumferential-side end portion of each of the upper pieces and the lower pieces so as to press the side rails, and a through hole being formed in the flange portion,
wherein a side rail support portion of the spacer expander is formed at an end portion or an intermediate portion in the circumferential direction of an outer circumferential-side end portion of each of the upper pieces and the lower pieces: wherein a length of the side rail support portion in the circumferential direction is shorter than a length of each of the upper pieces and the lower pieces in the circumferential direction so as to form spaces between each of the upper pieces of the spacer expander and the upper side rail, and between each of the lower pieces of the spacer expander and the lower side rail, at portions other than side rail support portions in the circumferential direction of the outer circumferential-side end portions; wherein a length of the side rail support portion in the radial direction is less than half of that of upper and lower pieces except flange portions in the radial direction; wherein a portion inward of each of the upper pieces and lower pieces from an inner circumferential side of the side rail support portion to a base portion of the flange portion radially is formed as an inclined or stepped surface such that a gap between the surface and an opposing side rail thereof is widened in a direction radially inward from the inner circumferential side of the side rail support portion to the base portion of the flange portion.